Circuit interrupter



G; R. RADLEY.

CIRCUIT INTERRUPTER.

APPLICATION FILED "n.30, 1920.

Patented Dec. 5,1922..

Patented Dec. 5, 19212.

UNITED STATES PATENT OFFICE.

GUY R. RADLEY, or MILWAUKEE, WISCONSIN, AssIGNOR rro THECUTLER- A MEG. CO., or MILWAUKEE, WISCONSIN, A CORPORATION OEIWIsaONsIN.

CIRCUIT INTEBRUPTEB.

Applicationvled April 30,

To all 'whom it may concern:

Be it known thatl, GUY R. RADLEY, a citizen of the United States residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Circuit Interrupters, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forminga part of this specification.

his invention relates to circuit interrupters. y

One object of the invention is that of providing a circuit nterrupter of the character stated which, while posit-ive and reliable in operation, is nevertheless of small and compact construction and moreover. adapted to cheap and economical manufacture.

Another object is that of providing such a Vcircuit interrupter which may be advantageously employed as a circuit breaker.

Another object is that of providing a cir- .cuit interrupter of the character stated, having means adapted to effect response thereof either electromagnetically or electrothermically under different degrees of energization thereof respectively.

Another object is that of providing a circuit interrupter utilizing the aforcdescribed characteristics for `vrendering. the device of the inverse time element type.

Other objects and advantages will hereinafter appear.

In the accompanyin drawing, Fig. 1 is a front e evational view illustrating yone of the embodiments which the invention may assume in ractice;

Fig. 2 is a similar view 1 lustrating a modirfied construction and arrangement, while,

Fig. 3 is a side view, partly in section, of the device illustrated in Fig. 2 but viewed from a different horizontal angle.

Referring to Fig. 1 of the drawing, the same illustrates a circuit interruptercomprising a fixed contact 5 and a pivotally -mounted co-operating contactor arm '6, the latter being biased out .of engagement with said fixed (Contact b means of a spring 7. A medially pivoted atch 8 of magnetic material is adapted to co-Operate with a studl 9 of said contactor arm to normally maintain the latter in Contact making position against the bias of said spring, a tension spring 10 serving to resiliently old said latch in engagement with said stud,while a combined 1920. semi N. 377,161.

electromagnetic and thermostatic element 11 serves un er predetermined electrical conditlons to trip said latch `for release of said arm and opening of the switch. All of the foregoing parts are carried upon a suitable base or panel 12.

The element 11 comprises a thermostatic strip of substantially annular contour preferably bimetallic in character and having at least one of its constituent parts composed of a ferrous or other readily magnetizable material. Said strip is surrounded throughout all or a major portion of its length by a coil 13 of insulated electrical conductor whereby passage of current through said coil serves both to magnetize said strip, and also to heat the same for varying the contour thereof to degrees dependent upon the degrec and duration of such energization.

aid strip 1s provided at one end with a substantially straight outwardly projecting portion 14 which in practice is rigidly secured to the panel 12 to serve as a support A magneticA block or pole for. said element. piece 15 is secured to the side of said projecting portion 14, said pole piece serving to concentrate at thisvpoint the magnetic flux induced by the coil 13.

The opposite end of said element has rigidly secured thereto a substantially L- shaped insulating and non-magnetic member 16 adapted to be moved radially outward upon increase in temperature of said element;

Said element is so arranged upon the panel 12 as to effect location of the insulat- 1ng member 16 and the pole piece 15 beneath and closely adjacent to the latch 8 upon opposite sides respectively of the ivot thereof, whereby straightening of said) element under thermic' influence of the coil 13 tends to lift and trip said latch, whereas electromagnetic ener ization of said element and its attached po e piece similarly tends to tri the latch throu h attraction of the 100 tail piece thereof. vIn te construction illustrated the coil 13 is connected as an overload, although obviously such arrangement ma be varied in practice.

'IYhe aforedescribed parts are lpropor- 105 tioned and arranged to be both thermostati cally and electromagnetically unresponsive for all values of current through the coil 13 below a predetermined value, whereas for vmoderate increases in value of the current i above such predetermined value the tension of the spring l0 is sufficient to prevent electromagnetic tripping of the latch 8. However, should such overload persist for a suflicient period of time, such e'riod being variable substantially inverse y with the degree of the overload, the coil 13 and the element 11 surrounded thereby become sufficiently heated to effect thermostatic tripping of said latch and consequent interruption of the controlled circuit. Also for overloads of stillhigher magnitude, as for example, three times the normal value assuming the use of direct current or six times the normal value assuming the use of alternating current, the electromagnetic attraction of the tail piece of the latch 8 by the element 11 and the pole piece l5 overcomes the tension of the spring 10 for effecting immediate tripping of the latch and permitting practically instantaneous opening of the switch.

Referring n ow to Figs. 2 and 3, the same similarly disclose a circuit interrupter comprising a pair of stationary contacts 20 and 21 carried by a panel 22 and adapted to be bridged by a movable contact 23, the latter being carried by and insulated from an os'- cillatable lever 24 which is loosely mounted upon a shaft 25 and biased out of contact making position by means of a spring 26.

A magnetic spool 27 having a winding 28 is rigidly secured to the anel 22, said shaft 25 being journaled wit in and axially of said spool and being composed of magnetizable material. A fusible connection between said spool and said shaft serves under normal conditions to prevent relative rotation thereof. Said connection may in practice comp-rise a body 29 of sealing Wax, or other material having suitable properties, filling the space about said shaft within the spool 27.

A ratchet wheel 3l -is rigidly secured to said shaft 25 while a pawl 32 is pivotally mounted upon the lever 24 to co-operate with said ratchet Wheelfor preventing movement of said lever under the bias of the spring 26. A tension spring 33 serves to yieldingly hold said pawl in' operative relation to the teeth of said ratchet wheel, said pawl having a handle portion to provide for manual tripping thereof when 1t is desired to open the switch.v

'The pivot 34 of said pawl is elongated to provide for axial shifting of the latter out of the plane of the ratchet wheel 3l for disengagement thereof. An elongated resilient amature member 35 is secured at one end to the -lever 24 adjacent the free end of the latter, said amature member extending along said lever and terminating iny proximity to a projecting polar extremity of the shaft 25 to be attracted thereby, said armature member being curved outwardly to provide a suitable air gap therebetween. A pin 36 is arranged to project through the arm 24 and to terminally abut said armature member 35 and the pawl 32 respectively whereby upon attraction of the former toward the shaft 25 said pin serves to force the pawl laterally out of engagement with the ratchet wheel.

The operation of this construction is similar to that aforedescribed. Thus for energization of the coil 28 corresponding to normal values of current in the supply circuit, the device is inactive, whereas upon moderate but prolonged overload the heat developed by said coil serves to soften the fusible connection 29 thereby Apermitting the shaft and switch lever to move jointly to off position under the bias ofthe latter, while under condition of heavy overload the armature 35 is immediately drawn in thus disengaging the pawl from the ratchet wheel and permitting practically instantaneous independent movement of the switch arm to oftl position. In both of the foregoing constructions the switch arm may be released and permitted to move to open position through manual tripping of its restraining latch and may' be im mediately reset following opening movement thereof. Also, assuming release to have been effected electromagnetically, the switch arm following resetting will be maintained in closed position during continuance of normal current conditions. However, upon resetting immediately following thermostatic release, the switch arm must be held in closed position for a short period, in the one case to permit contraction of the thermostatic element and in the other case to permit setting of the fusible connection.

In practice in each' of the described constructions the thermoresponsive element thereof is preferably enclosed within a suitable covering for purposes of protection and also to render the characteristics thereof as regards sensitiveness to positive and negative thermic variations similar or analogous to those obtaining within the motor or other translating device which it is desired to protect.

What I claim as -new and desire to secure by Letters Patent is:

1. In a circuit interrupter, the combinaing netically and electrothermically selectively. under different electrical conditlons.

2. In va circuit interrupter the combination with a switch, of a winding and tription, with a switch, of a winding for eiectan operation of said switch electromagl 3. In a circuit interrupter the combination with a switch, and latching mechanism therefor, of a winding and a plurality of 1,487,617 y i a tripping means under the influence of said releasable restraining means therefor, of au- Windin one of said tripping means being tomatic tripping means for said restrainin adapte to trip said latching mechanism unmeans including an element adapted to e der given electro-magnetic conditions of feet both electromagnetic and electrother- 5 said Winding and another being adapted to mic influences and means to be subjected to 25 trip said latching mechanism under given such influences for response thereto selecelectro-thermic conditions of said winding. tively under different conditions of the con- 4. In a circuit interru ter, the combinatrolled circuit.

tion with a switch biase toward onevposi- 6. In a circuit breaker, the-combination 10 tion and releasable restrainin means therewith a switch biased toward one position 30 for, of automatic means for e ecting release and releasable restraining means therefor, of said restraining means including an eleof automatic tripping means for said rement adapted to act electromagnetically and straining means including a magnetizing substantially instantaneously under predeand heating coil and means responsive to the 15 termined electrical conditions and electroelectromagnetic and electro-thermic influ- 35 thermically subject to delay under other ences of said coil selectively under diiferent electrical conditions to trip said restraining electrical conditions of the controlled circuit. means. In witness whereof, I have hereunto sub- 5. In a circuit breaker, the combination scribed my name. 20 with a switch biased towardv one position and GUY R. RADLEY. 

